Split guide blade for centrifugal pumps



July 29, 1930. w. HAHN 1,771,711

SPLIT GUIDE BLADE FOB CENTRIFUGAL PUMPS yFiled Jan.1'7, 1929 2 sheets-sheet 1 mv D N JCI/1%@ July 29, 1930. w. HAHN 1,771,711

SPLIT GUIDE BLADE FOR CENTRIFUGAL PUMPS Filed Jan. 17, 1929 2 Sheets-Sheet 2 gld/W1 1 Patented July 29, 1930 UNITED STATES PATENT orFic-l-zl WILHELM HAHN, OF HEIDENHEIM-ONTHEBRENZ, GERMANY, ASSIGNR T0 J'. M. VOITH, 0F HEIDENHEIM-ON-THE-BRENZ, GERMANY, AVCORPORATION 0F GERMANY SPLIT GUIDE BLADE FOR GEN'IIR'III!"UGAL PUMPS Application led January 17, 1929, Serial No. 333,050, and in Germany January 19, 1928. v

The invention refers to split guide blades for centrifugal pumps consisting of a fixed and a movable part.

Guide blades are known on which the mov- 5 able part of the guide blade situated next to the runner wheel is so arranged that -the pivot is at the end opposite to the runner and immediately before the fixed part of the blade (seen in the direction of flow). This design 10 has the disadvantage that by the blade being suspended at one side of the pivot large powers have tobe transmitted so thatoften breakages occur, and further v such blades tend to vibrate and to chatter, thus prejudicing the smooth running and by the favoured moving away 4of the stream from the blade also the efficiency of the pump.

The object of the invention is a'split guide blade consisting of a movable part and a fixed part on which the part turned to the runner wheel is supported by a journal arranged about in the middleof its length and at its opposite end so bevelled thatv with quite opened position the turnable part is pressed by the water pressure to the iixed part forming with this afbody of a constantly limitedA cross section so that a chattering of the blade is impossible.

By the fact that the movable blade is supported in its middle the forces acting upon it are more or less balanced.

In making blade adjustments the guide vane gear for governing the movable part of the blade is turned in the closing direction, thusV reducing the clearance at the entrance of the blade; at the same'time the bevelled end moves away from the fixed part producing between the two partsof the guide blade a gradually extending channel. Vith a correct bevelling this channel adapts itself to the flow sothat in the guide vane gear a system is formed of channels constantly extending in the direction of How, in which -the velocity of discharge from the impeller is favourably changed into pressure.

Figures 1, 2, 3 andl 4 show an example of the invention. Fig. 1 represents a longitudinal section through a centrifugal pump with double inlet with which the guide vane gear shows the form according to the invention, Figs. 2 and Brpresent a partial section ary part in a .larger reproduction. Bearings (l) support shaft (2), on which is arranged double runner (3) It is enclosed b housing (4) supporting on both sides dra elbows (5), to which are connected draft tubes (6). The guard rings for guide Wheel cover `(7) forming the continuation of housing (4) outwards are pierced by Shanks (8), around which the movable parts (9) of the guide vanes may be turned. The are sup ported at their outer ends by the' xed guide vane parts (10), along the bevelledends (11). Outside of the guide vane rim the pump housing passes over into the spiral casin (12). Shifting ring (13) acting upon gui e vane Shanks (8) by means of levers (14) serves to adjust the guide vanes. In the partly closed position of the guide vanes, as it is represent. ed by Fig. 3, channels (15) are visible -between the movable parts (9) and the iixed parts (10).

In order to obtain the eect set forth the bevellingat the movable part mu'st be made according to Fig. 4. It can be made straight or'curved, but in any way it must adjust itself with suflicient rounding off at the point 16 to the other roile of the movable part. The position of' evelling to the fulcrum is determined by the stipulation that the diffuser angle e, which-is formed by the wallsof the channel arising by turning the guide vanes, is

not larger than about 14a, becauseotherwise in this channel the flow moves away from the walls. The angle of thevchannel depends how far the movable guide vane parts for governing must be turned in the closing .di-

This is different from one time to The above mentioned stipulation,

rection. the other.

^ that the angle of the channel shall not exceedV the channel, (8) the angle formed by the two radii and (l) the length of the channel -18, then between torsional angle (qu) and diffuser angle (e) results the following relation:

The value of e to be calculated from it for the highest value of should not be greater thanabout 14.

Claims:

l. In guide blades for centrifugal pumps, stationary and movable blade sections arranged incircumferentially spaced pairs around the runner-wheel of' the pump, the

blade sectionsin each'pair having coacting opposed ends, and themovable blade section being constantly urged by the pressure of water owing between the spaced pairs of blade Sections into abutting contact with the end of the,fixed blade section to provide a lWater passage between said' spaced pairs of bladesections of definite predetermined area, and the movable blade sections adapted to be moved relative to the fixed blade sections to provide water diverting channels between the opposed ends of the fixed and movable blade sections extending in the direction of flow of the water through said passages.

2. In guide blades for centrifugal pumps, pairs of blade sections arranged around the runner wheel of the pump in circumf-erential- A ly .spaced relation, the blade section in each pair contiguous to the runner wheel being pivoted intermediate of its ends and having one of its ends bevelled for abutting contact against a bevelled end of the outer relatively fixed 'blade section by the pressure of water @owing between the spaced pairs of blade sections to thereby provide ow directing passages of definite area, and said pivoted blade sections adapted to be moved relative to the xed blade sections to constrict the inner dlscharge ends of said passages and-provide Water diverting channels between the opposed ends of the fixed and movable blade sections extending in the direction of flow.

In testimony whereof I affix my signature.

DR. WILHELM HAI-IN. 

